The reason why a digital computer has made progress as a programmable computer can be conceived that the size and the capacity of a digital memory has rapidly advanced into small and large, respectively, than an analog memory, But recently, it is close to the limit to produce higher density of digital LSI: the development of a digital computer has the limit without doubt. Conventionally, the scale of a circuit is large and the process of the production is complicated in order to realize a memory in analog or in multilevel.